I teach an introductory course on mammal identification and natural history. This blog serves as a place for all of those stories, photos, facts and fun stuff that simply won't fit in the course. Type in your email below to follow this blog!

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Thursday, March 21, 2013

Black Bear Den Season 2013 Part III: The final chapter

Beautiful view while waiting
at a bear den
(Almond, NY 3/13)

Last week we visited two more dens to round out our 2013 season. As I mentioned in my previous posts, my students take on the role of undergraduate researchers at these dens. We have a long term project gathering den data and when there are cubs present, we take the lead in gathering data for the NYS DEC to help age them. These two dens were fantastic successes in every way but could not have been more different. Fair warning: This turned out to be a long post :)

DEN #5: We found ourselves back in Region 9 (read: looong drive for us) last Thursday morning for one of the oddest dens I have ever seen. I was told the den would be on a Christmas tree farm, in a brush pile. Now, a brush pile is a very common den location in our area so that in itself was not surprising. What was unusual was the size of the brush pile! If my memory serves, we measured it at about 60 feet by 20 feet and ten feet high. The trick was for the biologist to hone in on EXACTLY where the bear was within this massive pile of uprooted evergreens. That work was done a few days before and it was determined the female only had a single entrance (and therefore exit) to the den. That would increase the chances that the female would remain in the den after being darted. We were allowed to within about a 100 yards of the den to wait while the advance team made their way in.

Bear den in the center of this massive brush pile
(Almond, NY 3/13)

Take a good look at this massive pile. These are all uprooted Christmas trees and certainly make a great fortress of solitude. Below is a somewhat closer look:

That is Jeb there are on the right and Art up top at the specific den location.

Everything went well and we were waved in promptly. There were three cubs at this den and once they were handed down from the den, we set to work taking our measurements.

NYS DEC Region 9 staffers

As I have stated before, the cubs get sexed and weighed. We then measure both hair length and ear length in order to determine cub age based on research done at the University of Virginia. Finally, each cub receives a PIT tag implanted just under their already thick hide between the shoulder blades. During this process, all cubs stay warm in their fleece bags (except for a brief check for gender) and on a cold day like this, the fleece bag often goes under the coat of the person holding the cub. Cubs are never handled with our bare hands (ironically) and no one cuddles, snuggles or otherwise treats them as pets. My students are here as part of their formal education in a transition from amateur to professional and they look and act the part. I am extremely proud of them and can no longer go to a den visit without running into several of my former students working for the State or are present in some other professional capacity. At this den, there were three FLCC alums.

FLCC students gather den data

In order to get everything done in a short time, the duties are divided among the group. So concurrent to the cub data collection, another group of FLCC students is taking den characteristic data. This was a project conceived of by the DEC staff in order to better understand this important aspect of bear behavior. Work has been done in other locations regarding den site selection and characteristics, but that information does not translate well to other areas of the country. Even information from within New York State is not applicable to us as we have a completely different environment here than say the Adirondack Mountains to our north. I am proud to say we now have data from about three dozen dens over several years and are ready to report on our findings. But that is another story all together...

Meanwhile, a third group is working with the adult female. Often the radio collar is changed or removed (depending on the research question and other factors) and the bear must be constantly monitored while she is chemically immobilized. Here, Wildlife Biologist Art Kirsch acts as note taker.

Data collection is an important job

Checking the CRT on a black bear

In this particular instance, the adult could not be easily removed from the den, so a single person entered the den to monitor her health. Dr. Jeff Wyatt, a veterinarian with the Seneca Park Zoo was on hand to take TPRs (temperature, pulse and respiration). Basically, he is looking for any change in these numbers. A drop in temperature may lead to the bear being covered in a "space blanket" to retain heat (conversely. if we were working in the summer we may have ice packs on hand in case the bear overheats -- no danger of that in THIS day). Pulse can be taken directly in the traditional manner or indirectly by looking at something called "capillary refill time" (CRT). In this case, the vet pushes his finger against the gums of the bear. This causes the tissue to turn white as the capillaries are emptied in the process. Then the finger is removed and the observer counts how long it takes for the color to return. In essence, this is a way to measure the pulse of the animal as the faster the color returns, the harder the heart is pumping the blood. Make sense? As with the temperature or respiration, the thing to look for is a change. If the pulse drops, that may indicate an adverse reaction to the drugs. I can thankfully say that in all my years of attending den visits, I have yet to see a problem.

It didn't take long before we were done and the cubs were ready to be returned. We formed an impromptu bucket brigade to return them to the den. As we walked away I kept thinking of how much fun these cubs were going to have playing in their giant jungle gym.

NYS DEC heading to bear den

Den #6: Our final den visit of the year was the next day in Steuben County. The drive was a bit closer for us and it was a particularly special day for me because I got to bring my daughter along. She is a junior in high school and we truthfully told her school she was visiting a college class :) . We arrived at the den location and met the homeowners. Although most landowners are pleasant, this couple stands out to me as particularly thoughtful and kind. Perhaps that is why this bear chose a den location that was a mere 70 yards from their back door. That's right, 70 yards. They have a dog pen in the back yard and I couldn't help but think that even though the humans didn't even know the bear was there, the dog must have been able to smell her and her cubs.

Danika Van Niel with bear cub

Again, everything went smoothly with the immobilization of the sow. She had two cubs, one of each gender. At right is my daughter Danika. She had a great experience and you can see it in her face. The mother and cubs were healthy and it should be noted again how close they were to the house. I think this is important for a few reasons. First, it is interesting that a bear can be this close to people and the people didn't even know. That my friend, is the definition of a good neighbor. Second, think about this from the bear's prospective. Why did it chose this location? Was this a prime "favored" location or was this bear here because it couldn't hold a better territory?

We took our usual measurements with some help from Ron Newell, a DEC Technician. Ron is scheduled to retire this summer, so this was probably our last den visit together. Ron has always been particularly helpful with my students, always remembering to explain the procedures to them and making them feel comfortable. Thanks Ron!

Ron Newell weighing bear cub

The veterinarians from the Seneca Park Zoo brought a new gadget with them to help monitor the adult sow: a pulse oximeter to measure blood flow.

You can see it is attached to the bear's tongue.This is non invasive and very interesting to see.

I went to check on the students at the actual den to see their progress. All was going well. Again a bear selected a thorny brush pile. In this photo, Judi is at the actual entrance of the den proper taking measurements.

The den had a small depression and the now familiar "nest". We were nearing the end of the visit and the sow had already been moved into the den. The biologists were rounding up the cubs and I called Danika over and told her where to stand so she could be part of the "cub brigade". Here she is handing a cub over for the last time.

As the biologists stepped back, I asked if we could sneak in for a quick photo. Sure, they said. I laid down and snapped a few photos of the sow and her cubs. I want you to note a few things in this photo. First, see that they have placed the female's paw over her eye to keep it protected from the light until she can wake up and blink again. Next, note that the cubs are already nursing. Bears have three sets of teats: two in the torso region and a third set near the groin. These cubs are nursing on these lower nipples. Third, notice the yellow ear tag. Finally, take a look at the den itself. We try hard not to remove any cover so what you see is what she chose. A few of the grape vines are broken, but she did that for den material.

Danika was the last to take a look. Here she is taking a short video of the action in the den:

The video is nice. It makes you feel as if you are there. And if you listen carefully, you may even hear a little suckling from the cubs